Two stage fluid pressure cylinder



Sept. 18, 1951 H. D. FORSE. 2,558,228

TWO STAGE FLUID PRESSURE CYLINDER Filed Oct. 51. 1947 2 Sheets-Sheet 1 ATTORNEY Sept. 18, 1951 H. D.-FOR$E 2,568,228

TWO STAGE FLUID PRES URE CYLINDER Filed Oct. 31, 1947 2 Sheeta-Sheet 2 ATTORNEY Patented Sept. 18, 1951 UNITED-- STATES '2;5es,22s I 7 TWO STAGE-FLUID PRESSURE iovnlnneit V Harry D, Forsa iindersomlnd; v H 1 Application oetebersi, 194-7,Serial No. 78 3,321 oiai fii; (01. 604)?) This invention relates to improvements in power transmitting apparatus and more especially-to such apparatus for delivering a power stroke of limited force during the initial and intermediate portions-of the stroke and ef increased force thereafter. i

The improved-apparatusof this invention is especially adapted' for use in operating laundry and garment finishing presses and other equipment wherein a two step-operation-or power stroke is both advantageous anddesir-a'ltile. In such an arrangementpthepressing headis moved from an open position into'pressing position, wherein the pressing-elements are in predetermined spaced relation, under the infiuenceof a limited pressure and then to apply increased pressure to the head; it is to' be noted that both safety and economy factors ashereinafter more fully explained, are involved -in the use of the limited initial moving force. Only a f-ter-the head has been moved into its predetermined pressir-ig position is operating --pressure delivered to -the'apparatus for the pressing-operation. While the present disclosure associatesthe improved at)- paratus with a :garmen-tpress, it will be apparent that its use is not confined to such a limited field.

Several varieties of power transmitting apparatus have from time to time appeared on the open market. These, however, have notmet with completepublic approval du'e'to their high initial cost, excessive maintenance required for the numerous intricate parts; high operating costs, and theirw erratie and u-ndependable operation. Moreover some of these prior structures included numerous close fitting parts requiring costly clos tolerance machine work in production and frequent and delicate adjustment in operation.

Accordingly it is one of the chief objects of the present invention to provide a sturdy and rugged device consisting of but relatively few economically produced and easily assembled parts which in operation function accurately and precisely over long periods of hard use with little, if any, attention or maintenance care.

Another object of advantage and importance of the improved apparatus is the provision of "means for arranging two pressure responsive units .in .tandemrfor independent sequential operation in delivering a single power :stroke.

A further object of importance and advantage resides in the provision :of means for energizing thesecond actuated unit to impart an "increased pressure only "after the first operated unit has pompletedv its lighter pressure delivering opera- Mam etite-e tlon This,cflnstl-tlltefiiaigsai fi y iactor fo DIE? venting injury to an operator p Y Another and stillyfurtheriohi'ectof impo tance and advantage isithe provision of controhmeans for, operating the tandem arranged pressure ,re:

sponsive units in raltg enuseqll nce du n 1 .1% power stroke and-of ire-versingthe. eq nce. 92 e eraiien for :theretum movem nt o t eimits; Still another object. Df advanta e a d mPQI: tance is the provision :of zmeansi lill k n .Q first operated unitagaiitnste u fir, nd p nd t operable movement when the in tial step is (30111 pleted. l h I n additional object :of. impor anc resides-" n the provisionxof means ior-utiliz n xl tent means operated by the energization ofIlih 6 1 ib for preventing inadvertent n ockin of. the locking means, during the oper le movem nt. of the second operated unit. Additional objectsnf advantage and impor: tance will becomeiapparentxas the :iollowing detailed descriptienpro resses, r fe nc bein d to the accompanying drawin s, whe n Figure 1 is a side elevational view-of apower transmitting apparatus which ,emboidies the in vention. Control elements, for operating the ap paratus are diagramma mally eshownt A e 1 Figure =2,is :a similar view of the apparatus in a different operating position, partsthereof being broken aWay., Figures 3 and -311 are vertical sections taken on lines v33 and Sine-3a, resnectivelmnf Fi ure2.. Figure ads. a slightly enlarged longitudinal section of a f'ragmentalportion 30f :theapnaratus- The larger unit is :shown in partly; extended no: sition and the smaller nnitunarts of. w ch are broken away, :is shown iinitully. ;extended position. Figure 5 is a-longitudinail sectioned :a slightly modified form of the invent-ion, parts thereof @being brokenaway. V a v v Figure 6 yisja similr-sview showin theianpae :r-atus in a diiierent operating qziosition.

.Figure '7 isia yenticalssectionitaken mane-1H1 of Figure .6, and

Figure ,8 a vertical section :taken 011 Iline i8-:8 of Figure :5. .i p 1 In the embodiment oi zthis inventioniilllistrated Figures ljtoA, inclusivawf the drawings, :the referencenumeral :1 [1 indicates eenerallya pres- .sure responsive unitncomprising RB, .il 2 in which :a piston :l-4-;isoperably lp0S ltiQ'IIBI1.L. whe ieylinder is iprovidediwith heads-1'5 and E'Ifi' mhivh are preferably secured in ,position by bolts-r11 and iii? and is ventedias at 1 9. .JCE'he rhead :lii'nis 2pm,-

vided with an anchor stud 20, or other securing means, for attaching the apparatus to a suitable base, not shown. The head I5 is apertured to provide a port 2| for the passage of operating fluid to and from the cylinder |2. Extending from the head l6 and. concentric therewith is a boss 23 through which a piston rod 24 extends. One end of the piston rod 24 is attached to the piston M, as by a screw 25 or the like. The screw 25 also functions to maintain an expansible cup 26 and Washer 21 in operable association with the piston I4, as is best shown in Figure 4.

The extending end of the piston rod 24 is enlarged to provide a head 30 for a cylinder 3| positioned in axial alignment with the piston rod 24. An apertured head 32 is positioned on the extending end of the cylinder 3| and the unit, indicated in its entirety by the reference numeral II, is secured in operable position by a plurality of tie bolts 33. Thus pressure responsive unit it] and pressure responsive unit II are operably secured to each other.

Operably positioned within the cylinder 3| is a piston 34 to which a piston rod 35 is attached. The rod 35 extends through the aperture in the head 32 and the extremity thereof is threaded, as at 36, to receive adjustment nuts 31 for a yoke 38. The aperture in the head 32 functions as a guide for the piston rod 35 and this aperture may be of sufficient size or shape to vent the cylinder 3|. In addition thereto a vent port 40 is located in the cylinder 3| closely adjacent the head 32.

The head 30 is provided with a port 4 I, in which a nipple 42 may be secured, through which operating pressure is directed to and from the cylinder'3|.' Secured to the cylinder 3| intermediate the ends thereof is a nipple 43 which through a plurality of small perforations 44 in the cylinder wall communicates with the interior thereof, see Figure 4. These perforations 44 in conjunction with the piston 34 provide a control valve for the unit H] as hereinafter more fully disclosed.

A double toggle element comprising a pair of hingeclly joined bars 46 having their free ends operably joined to studs 41 projecting radially from the head 30 and yoke 38, is adapted to be moved to and from straight line position upon extending and retracting movement of the piston rod 35. The hinge is indicated by the reference numeral 45. In view of the fact that the hinged toggle bars 46 and their supporting studs 41 are precisely the same only one set is shown in Figures 1 and 2 of the drawings. Secured to the central portion of the toggle 46 closely adjacent the hinge 45 is a curved combination spacing and abutment member 49. Upon movement of the toggle 46 into straight line position, the member 49 engages the lower portion of the head 32 and thereby limits the upward movement of that member.

Extending beyond the end portion of the toggle 46 is an arm 50 which is recessed as at 5| to receive a stud 52 projecting from the boss 23 when the toggle 46 is in the position in which it is shown in Figure 1. The upper portion of the arm 50 extending beyond the recess 5| is flat, as is clearly shown in the drawings, to engage and be moved along the lower peripheral surface of the stud 52 when the toggle 46 is in straight line position and is moved longitudinally relative to the studs 52. The studs 52 in cooperation with the fiat surfaces of the arms 56 provide a detent means for maintaining the toggle 46 in straight line position. Thus the toggle provides a means for locking the piston 34 andpiston rod 35 in a predetermined position, as for the application of increased pressure by the unit l0, and the detent means prevents the locking means from being inadvertently released.

A pressure circuit for operating the improved apparatus is shown in dotted lines in Figure 1 and comprises a supply line 55 in which is positioned a three Way valve 56 for the manual operation of which a suitable handle 51 is provided. The valve 56 is normally biased to closed position so that the interiors of both cylinders l2 and 3| are in communication with atmosphere through an exhaust line 58. A flexible conduit 60 extends from the three way valve 56 to the nipple 42 and is adapted to convey operating pressure to and from the apparatus. A second flexible conduit 6| extends from the nipple 43 on cylinder 3| to a nipple 62 in communication with the port 2| in cylinder l2. This conduit 6| directs operating fluid to and from the pressure responsive unit ID as will hereinafter more fully appear.

Operation In the operation of the improved apparatus of this invention it will be assumed that the anchor stud 26 is suitably anchored and that the threaded end 36 of the piston rod 35 is operably connected to the load to be moved. Now with operating pressur available in the supply line, the handle 51 is depressed to open the valve 56. As a result of this action the exhaust 58 is closed and operating pressure is delivered through conduit 60 and port 4| into the left end of the cylinder 3 Responsive to this flow of operating pressure the piston 34, piston rod 35 and yoke 38 carried thereby are moved longitudinally to the right as viewed in the drawings. This movement of the piston rod 35 and associated parts straightens the toggle element 46 so that the piston 34 and piston rod 35 are rigidly secured against movement relative to the cylinder 3|. It is to be noted that when the apparatus is in this position the combination abutment and spacing member 49 is hearing against the under surface of the head 32 and the arm 50 engages the stud 52. During this portion of the operation the load, as for instance a pressing head, is moved from an open position into spaced association with its complementary pressing buck under a relatively light force. However, if some object of greater thickness than the predetermined space between the confronting pressure elements, as for instance an operators hand, is interposed between the buck and the descending head the relatively light operating force is incapable of moving the apparatus into its locked up position.

As the apparatus moves into its locked. up position the movement of the piston 34 uncovers the plurality of perforations 44 through the cylinder wall to supply operating pressure to the pressure responsive unit In. This operating pressure flows through the nipple 43, conduit 6|, nipple 62, port 2| and into the left end of the cylinder I2. As the operating pressure builds up in back of the large piston l4, an increased force is applied to the locked piston rod 35 through the piston rod 24, head 30, toggle element 46 and yoke 38. Thus a pressing force of increased intensity is applied to the pressing elements or other load. Concurrently with the application of this pressing force and the movement of the unit II the flat surface of the arm 56 is moved into engagement with the stud 52 to thereby lock the toggle element 46 in straight line position.

Now when the pressing operation is completed, the three way valve 56 is moved to its exhausting position thereby-ciitting the supply of" operating pressure to the cylinders- I 2 and "31." the-pres weight'and the piston assembl -cs the iinit 11 returns to its starting position. it"i'stobe'fhere" noted that the above movement preventsiiirther exhausting of the large cylinder l2" through the three way valve-56t Thus residual pressure in the large cylinder is utilized to cushion the-re= turn movement of the parts and is'then-slowl'y bled-from the large cylindenthrough theperfd rations 44" and vent port iflas'the-large piston assumes its starting position.

Modification Whereit is so desired the improvedapparatus of'th'is invention may be modified to eliminate the toggle element by substituting-suitable looking means therefor. An illustrative embodiment ef'such a modification is shown in Figures '5 to 8 iii-elusive. l

In this embodiment a large pressure responsive unit 65 is associated: in tandem with a small pressure responsive unit 66 for operation with a pressure circuit similar to the one shown in Figure 1. I

The large unit Ecomprisesa cylinder 61 with suitable heads 68 and 69 andfa piston 18 which carries a pistonrod l I; The head 69 is apertured and provided with a boss 12 which functions as a guide for the piston-rod H projecting therethrough, as is clearly shown in Figuresi5 and 6. The unit 65 is provided with an operating pressure port'l3'in which a nipple 14 may be positioned and ave'rit port it.

Formed in the center of the-piston rod :1 l f'and extending longitudinally thereofie a ho it? in "which a plunger 17 is operably positionem One endof the bore 'i-iiis preferablythreaded; as-at I8; to receive a threaded nipple 80 which} in conjunction with a nut ill, properly secures a suitable expansion cup 82 to the piston ill. The end of the plunger Ti adjacent the nipple 18 is also provided with an expansion cup 83 of leather or other like material. An intermediate portion of the plunger Tl is restricted to form a conical portion 84 and the head thereof is provided with a vent recess 85. A helical spring 8'6 interposed between the leading end of the plunger 11 and the bottom of the bore it functions to bias the plunger toward the left as viewed in the drawings.

Formed in the plunger 11 intermediate the ends thereof is a plurality of radially disposed apertures in which hardened bushings 81 are positioned. The bushings ill are in alignment with the restricted portion 84 of the plunger 11 when that member is in its normal position as shown in Figures 6 and '7. Each bushing 8'! carries a hardened ball 88 which upon operable movement of the plunger ll moves between retracted and extended position, see Figures 5, 6, 7

neme-end-cnthe piston rod; I'l carries an ex'ei pa'nsioncu 91 which may"beseolireeinpositiom by asc'rew' 92or-other suitable-attachingmeans; Theelosed'end as of the cylinder 90 carries it threaded attaching stud St to -which a) loath H1? to-be moved may be adjustably' connected. This load may-beaweig-ht to be-lifted or a spring. to be opposed" and causes biasing of: the unitltolz the left' when pressure thereinis releasedi- Theclosed end 93 isprovided with: an operating. press-z sure port 95 in operable association with a; threaded-nipple 96. Formed-intermediate the ends"- of the cylinder 9D"and penetratingtlie Wall thereof: is a plurality of" small apertures: 91 connect withi-an outwardly extending threaded nipple-981:; v apertures flhare dis'pesed to operate in conjunce' iron with the cup 9! to provide .a-control' means. for controllingthe nowor operating. pressureztb and from the pressure responsive unitt imtha manner previously explained: in regard:v to: the; embodiment shown in Figures 1: to 4, inclusivei.

The open end of" the cylinder. 90 iswiprovided. with an -enlargedi portion 99 th add rigidity and strength tothe member and alsozto permitethe' interior wall of the cylinder to be: recessedztn form a-ball race I014 Itis to "be;notedthat-gthc ball race I01 inconjunction. with: 111381 balls 8- f-unction, upon operation of. the: unit 6.6.: and plunger 11 -to thepositionshown in Figureifi; to lock the cylinder til against. movement in either direction. I

' Operation of modified embodiment The operation. of. the modified embodiment above described is-inefiect similar to. theoperation of: the; first described, apparatus.- In! other: words, the small; pressure responsive; unit. :teis operated to a predetermined position-where; J is lockedv against: return movement andthen the large pressure responsiveunit 65" is operated to thereby deliver an increased: working .pressure'ior force through the locked up: unit 56. I

It is to be noted that the nipples 14; Stand 88 are in substantially the same locations as their counterparts on the first described embodiment. Consequently, the pressure circuit there shown may be employed without alteration for operatingeither embodiment. Assume now that the conduit 60 is connected to the nipple 96 and that the conduit 6| connects nipple 98 with nipple 14. Under such a condition and with the apparatus in normal position, as shown in Figure 6, operation of the valve 56 to open position closes the exahust 58 and directs a flow of operating pressure through the port 95 and into the right end of the cylinder 90. In response to the introduction of operating pressure into the cylinder 90 the cup 9| is expanded into air tight relation with the inner wall of the cylinder 90 and that member is moved from the position in which it is shown in Figure 6 toward the right. Upon the arrival of the cylinder 90 at a predetermined destination, as shown in Figure 5, the ports 91 are uncovered as also are the ball containing bushings 81. Coincidently with the uncovering of the ports 91 operating pressure is directed through the conduit 6|, nipple 14, port 13 and into the left end of cylinder 61 and thence through the nipple and into the bore 16. This pressure moves the plunger 11 to the right, overpowering the biasing spring 86 and by engagement with the inclined surface of the conical portion 84 forces the balls 88 into the ball race I01 thereby locking the cylinder in its extended position. The continued 110W of operating" pressure into the cylinder 61 now functions to drive the piston toward the right. which movement carries the locked unit 66 in a like direction thereby imposing increased force on the load connected to thestud 94.

..When the unit has been under the increased pressure for a suflicient length of time the operating handle 51 is elevated to operate the valve 56 to thereby terminate the supply of operatin pressure and to open the exhaust 58. The flow of operating pressure is now reversed, that is from the cylinder 61, through the port 13, nipple 1.4,.conduit 6|, nipple 98, ports 9'! and into the cylinder 90 from whence it passes through the port 95, nipple 96, conduit 60, valve 56 to be discharged through the exhaust 58. As this discharging operation takes place the piston 10 together with the piston rod H and unit 66 locked thereto are moved toward the left in unison due to. the biasing action of the load I02. As the pressure within the cylinder 61 andbore 16 is exhausted, the biasing spring 86 forces the plunger I! to the left and as the conical portion 84 of the plunger 11 moves into alignment with the balls 88. pressure exerted thereon by the segmental surface of the ball race llll under the urge of the returning cylinder 90 moves the balls 88 radially inwardly to the position in which they are shown in Figure 6. The parts are thus returned to their startingpositions and any re- .-sidual pressure .in the cylinder 61 is bled off through the ports 91 and the space between the wall of cylinder 90 and the piston rod II and the :now contracted cup 9|.

--It will be apparent from the foregoing that Iherein is provided-a highlyefiicient and. sturdy device with which atwo step or stage power stroke :may be delivered. Moreoverthe apparatus contains a safety feature wherein the automatically controlled second stage of increased pressure cannot be started until the limited pressure iniitialstage portion of the power stroke has been completed and locked. V Asit .will be apparent to those skilled in the art to which the improved apparatus appertai'ris' that numerous changes and widely difierent designs may be made without departing from the spirit and scope of the invention, it is intended that the embodiments herein disclosed shall be interpreted as illustrative only and not in a lizriiti-ng sense. Reference is therefore to be had to the appended claim for a definition of the limits of the invention.

I claim:

Fluid driving mechanism, comprising a cylinder of large diameter adapted for mounting in a device to be fluid driven, a piston movable in this cylinder, a hollow piston rod attached thereto also serving as the piston for a smaller diameter movable cylinder, the closed end of which is also provided with means for attaching to said device to be fluid driven, a spring restrained piston movable in said hollow piston rod, means whereby said hollow piston rod may be lockerd immovably to said smaller movable cylinder after said smaller cylinder reaches a predetermined position, control means for supplying fluid to said smaller cylinder and further control means for bypassing said fluid to said larger cylinder after said predetermined position has been reached by said smaller cylinder, means normally tending to bias the movable elements of the device to a start. ing position and means for exhausting all fluid from said device to permit said movable elements to return to said starting position under the urging of said biasing means.

HARRY D. FORSE.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS Number Name Date 270,760 Dederick Jan. 16, 1883 1,430,359 Canion Sept. 26, 1922 1,865,105 Houplain June 28, 1932 1,965,106 McDougall July 3, 1934 

